Aspects of the present invention are directed to premixed combustion systems and, more particularly, to gas turbine combustors employing premixed combustion systems as well as premixed combustion systems in other contexts.
Generally, gas turbine combustors employ premixed combustion systems that are designed to fully mix air and fuel prior to combustion. In this way, the gas turbine combustors are able to achieve lower emissions than comparative diffusion combustion system in which the fuel and the air mix as they burn.
Premixed combustion systems of gas turbine combustors are, however, subject to a failure mode called flameholding. In flameholding, a flame is initiated and then persists within a zone of the combustor that is intended for fuel mixing without burning. In detail, during normal operation, the flame persists at the discharge or burning zone of the nozzle (see region A in FIG. 1) while, during abnormal operation, such as the flameholding incident, the flame persists within the premixing annulus (see region B in FIG. 1) where the flame may cause damage as well as a failure of the low-emissions function of the fuel nozzle.